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Adaptation and self-fertilisation: from genes to genomes

适应和自花受精：从基因到基因组

基本信息

批准号：
NE/R015686/1
负责人：
Matthew Hartfield
金额：
$ 66.06万
依托单位：
University of Edinburgh
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2018
资助国家：
英国
起止时间：
2018 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FR015686%2F1
关键词：
Adaptation self fertilisation genes genomes

项目摘要

Why sex? Birds do it, bees do it, even educated fleas do it. Across the tree of life, sex is the predominant form of reproduction; explaining its prevalence has occupied some of the finest minds in evolutionary biology. Sexual reproduction can arise in various ways: in particular, many species are capable of self-fertilisation if they produce both male and female sex cells that can fertilise themselves to produce offspring. This form of reproduction is especially common in plants, but is also seen in many other organisms, including fungi, worms, pathogens, and some animals.This reproductive mode has a profound effect on how species can adapt to rapidly-changing environments, but we currently lack data regarding how genetic evolution is affected in species with this mode of reproduction. It was long thought that frequent self-fertilisation was an evolutionary 'dead-end', as it did not allow selection to efficiently remove unfit genes. However, mixed evidence exists for this theory, and it is also becoming apparent that high rates of self-fertilisation could also impede the fixation of adaptive genes. Understanding and quantifying how genetic evolution plays out in self-fertilising organisms will therefore shed new light on how organisms with different means of reproduction are able to adapt to rapidly-changing environments. This research topic also impacts on questions affecting society and agriculture. For example, many crops are highly self-fertilising, which enabled their rapid propagation after initial domestication. My goal is to unite state of the art mathematical analyses with genetic datasets, to create a complete picture of the process of adaptation in self-fertilising organisms. There will be two broad aims to my research. The first is to quantify what type of adaptation is prevalent in self-fertilising species. I will develop a suite of statistical methods to determine the prevalence, strength, and type of adaptation in selfing species. In particular, I will find out if adaptive genes arise from new mutations, or instead if they were created from either existing genetic variation that became adaptive following an environmental change, or recurrent mutation that reintroduces the new genetic variant. I will apply these models to data from a variety of organisms, including those that are important food sources for humans and animals.The second aim will be to carry out new theoretical studies to predict how self-fertilisation affects the evolution of multiple adaptive genes that are spread out throughout an individual's genome. I will first create mathematical models of how different degrees of self-fertilisation affect the spread of these genes if they act independently. I will next consider what happens if these adaptive genes then interact with each other, potentially favouring the appearance of fixed gene combinations and the spread of clones. I will finally determine how these phenomena feedback to affect the evolution of self-fertilisation itself.Overall, these techniques will help scientists understand what evolutionary forces underlie the appearance of self-fertilisation, and shed light on why reproductive modes are so diverse and flexible in nature.

为什么是性？鸟类如此，蜜蜂如此，甚至受过教育的跳蚤也如此，在整个生命之树中，性是繁殖的主要形式;解释它的普遍性已经占据了进化生物学中一些最优秀的头脑。有性生殖可以以各种方式出现：特别是，许多物种能够自我受精，如果它们产生雄性和雌性性细胞，可以使自己受精产生后代。这种繁殖方式在植物中特别常见，但在许多其他生物中也可以看到，包括真菌、蠕虫、病原体和一些动物。这种繁殖方式对物种如何适应快速变化的环境有着深远的影响，但我们目前缺乏关于这种繁殖方式如何影响物种遗传进化的数据。长期以来，人们一直认为频繁的自花受精是进化的“死胡同”，因为它不允许选择有效地去除不合适的基因。然而，这一理论的证据参差不齐，而且越来越明显的是，高自花受精率也可能阻碍适应基因的固定。因此，了解和量化遗传进化如何在自花受精的生物体中发挥作用，将为具有不同繁殖方式的生物体如何适应快速变化的环境提供新的线索。这个研究课题也影响到影响社会和农业的问题。例如，许多作物是高度自花受精的，这使得它们在最初的驯化后能够快速繁殖。我的目标是将最先进的数学分析与遗传数据集结合起来，以创建自受精生物体适应过程的完整图像。我的研究将有两个广泛的目标。第一个是量化什么类型的适应在自花受精的物种中普遍存在。我将开发一套统计方法来确定自交物种适应的普遍性、强度和类型。特别是，我将发现适应性基因是否来自新的突变，或者它们是否是从现有的遗传变异中产生的，这些遗传变异在环境变化后变得适应性强，或者是重新引入新遗传变异的复发性突变。我将把这些模型应用于各种生物的数据，包括那些对人类和动物来说是重要食物来源的生物。第二个目标是进行新的理论研究，以预测自受精如何影响分布在个体基因组中的多个适应基因的进化。我将首先建立数学模型，说明不同程度的自花受精如何影响这些基因的传播，如果它们独立行动的话。接下来，我将考虑如果这些适应性基因相互作用，可能有利于固定基因组合的出现和克隆的传播，会发生什么。我将最终确定这些现象是如何反馈影响自花受精本身的进化的。总的来说，这些技术将帮助科学家了解自花受精现象背后的进化力量，并阐明为什么生殖模式在本质上是如此多样和灵活。